engleski

The effect of concentration and pH on selectivity of ion exchange in system natural zeolite-Na^+/Zn^2+ aqueous solutions

The removal of zinc ions from synthetic binary solutions on natural zeolite clinoptilolite has been studied. The investigations were conducted to study the effect of concentration and pH value on the selectivity of natural zeolitic tuff (>80% clinoptilolite) for zinc ions. The results for different concentrations of binary solutions have yielded ion exchange isotherms that show sigmoid shape for all examined concentrations. This indicates a substantial unselectivity for zinc ions that decreases by the decrease of total concentration. The selectivity is significantly improved if solutions originate from acetate than from sulphate salts, and by increasing of pH in the solution from 4 to 5 or 6. This could be explained by changes of hydration energy of divalent zinc ion.

natural zeolite; clinoptilolite; zinc ions; ion exchange

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